If your windows or sliding doors have locks that slide vertically or horizontally, a simple paint trick will help you tell at a glance and from a distance if they're locked.

Reddit user HandCannon painted the bottom of the sliding glass door lock white, so it's easy to tell when the lock is in the locked position. An alternative is to use bright red and green paint: When in the locked position, show red, and when in the unlocked position, show it green.

Either way, with this easy trick you don't have to cross the room to check if you've locked your windows and doors.